1. Field of the Invention
This invention pertains generally to sorbents, and more specifically to bean cull manufacturing and utilization techniques which yield sorbents having many preferred characteristics. In one particularly preferred manifestation of the invention, small animal litters, such as are commonly used for cats and other small animals, are prepared from navy bean culls.
2. Description of the Related Art
As humans have become more technologically astute, a number of changes have swept through both home and industry. In an industrial setting, people regularly work with many chemicals and compounds in strengths and concentrations which either do not occur in nature, or which occur only infrequently. By using these modern techniques of processing and synthesizing, products which could not have been imagined only a few generations before are being manufactured or produced on a very consistent and reliable basis. People have, quite simply, learned much about how to synthesize, extract, concentrate, and combine various compounds and ingredients to better serve their needs.
As a by-product of these operations, there is a steadily growing need for improved ways of cleaning up from such operations, and better disposing of the wastes. Modern societies have evolved to include very dense populations, and the techniques used to clean up and dispose of the wastes will have a direct impact on how subsequent generations will be able to develop and utilize resources.
When liquids that may be noxious or hazardous are to be cleaned or removed, dilution such as would be achieved by washing is one option. However, in many cases dilution only leads to a greater volume of liquid which must be handled, without easing the handling at all. In some instances, dilution will only lead to the introduction of an undesirable compound into rivers and lakes, and may account for very undesirable pollution therein. Consequently, other techniques have been developed to provide better handling of such materials. One such approach is to use materials referred to as sorbents. These sorbents will most preferably retain liquid, sometimes at greater mass of liquid than mass of sorbent. The resulting combination of liquid and sorbent may then be handled generally as a solid. One characteristic which is frequently considered to be important then is referred to as sorbency, which for the purposes of this disclosure is calculated as the mass of substance sorbed divided by the mass of the sorbent. It will be understood for the purposes of this disclosure that the alternative spellings “sorbancy” and “sorbency” are understood herein to refer to the same meaning. Furthermore, the selection of the term sorbent, as opposed to absorbent or adsorbent, will also be understood for the purposes of this disclosure to be indicative of the different types of interaction that may occur with a sorbent and compound being sorbed, and may include various chemical, molecular, atomic, or surface interactions as well as simple permeation.
Within the home, needs similar to those of industry have developed over the last few generations. Homes of old were commonly little more than shelters designed to keep out precipitation, but were otherwise generally very open to the external air and environment. Relatively recently, people have found ways to use modern industrial products to seal such dwellings entirely from the exterior. Even air exchanges within a building are often carefully controlled today, to selectively introduce fresh air while minimizing the need for energy used in climate control. Consequently, with the sealing of a home from the exterior environment, the management and control of certain items within a modern house have also required more careful consideration, and bear many of the same needs as the cleaning and disposal of commercial and industrial wastes or by-products. One common household product which utilizes sorbents to capture and simplify waste disposal is animal litter. The handling of other liquids and waste products within a home or building present challenges and issues much like those of industry. Consequently, for home and commercial application as well as industry it is desirable to have suitable sorbents available.
The selection of base material for the manufacture of sorbents has historically been driven primarily by cost. When a source material was identified that had ready availability and low cost of production, such material stood a good chance of acceptance in the marketplace. Consequently, early sorbents were manufactured from materials such as clay and sand that could be dug from the earth with large scoops or shovels, and which required very minimal processing to be ready for use as a sorbent. Clay offers significant flexibility with the waste being sorbed, being able to sorb both water and oil-based liquids. Sand offers ready separation of liquids from solids, and is easily used to cover up or hide wastes. Since both materials are naturally occurring, returning these materials to the ground does not alter the ecological balance in any way. Furthermore, both materials are capable of withstanding very high temperatures, so where either pre- or post-processing of the sorbent using heat is desired, these materials have been desired.
In order to remain cost competitive, other materials that were identified as sorbents were selected from various under-utilized materials that might otherwise have been thought of as waste streams themselves. One example is the use of cellulose-fiber based sorbents, utilizing many different sources such as wood, corn and other agricultural stalks collectively referred to as straw, and the like. The use of such cellulose-fiber based sorbents has been particularly common throughout recorded time in the handling of agricultural waste, such as bedding for cows, horses and other livestock. The cellulosic agricultural waste products such as grain stalks are quite low in nitrogen, and proportionately high in carbon. As a result, these materials have, by themselves, tended to be difficult to biologically degrade either naturally or through ordinary composting processes. Nevertheless, the cellulose fibers act like wicks, and so are able to sorb significant amounts of liquid. When these liquids are high-nitrogen compounds such as animal wastes, the resulting fiber-and-waste combination is actually quite balanced in carbon and nitrogen, and so is readily composted and returned to the soil as a desirable soil amendment.
Consequently, for many years sorbents were manufactured almost entirely from clay, straw and cellulosic fiber as the primary ingredient. These materials still today provide suitable characteristic for many applications. However, since the introduction of commercial cat litter more than half a century ago, much development has been made in the field of sorbents which has had direct bearing on both home and industrial application.
Original cat litters were manufactured from various clays or sand compositions. Since then, litter compositions have become far more intricate and sophisticated, frequently including many different additives that are designed to enhance or introduce particular desired characteristics while minimizing other undesired attributes. Among the desired characteristics are sorbency, clumping, minimal expansion during liquid retention, odor masking or neutralizing, low bulk density, animal attractiveness, moderate textures, bio-compatibility, sewer and septic compatibility, and renewability. Undesirable characteristics include dusting, tracking or otherwise clinging to animal paws or fur, microbial growth, toxicity, wicking through the bulk after clumping, and clump friableness.
Since no material has been found to have all of the desired characteristics and none of the undesirable characteristics, the approach more recently has been to compose “designer” formulations that have additives and ingredients to optimize the specific features or characteristics that are desired in a given composition. These “designer” formulations may then be applied not only to households for cat and other small animal litters, but to many diverse applications requiring the use of sorbents. Unfortunately, this mixing of ingredients requires more technical savvy in the formulation and manufacture of a product, and associated higher cost. Furthermore, bio-compatibility, chemical interactions, and toxicity are much more difficult and complex to assess as additional ingredients and additives are mixed into any formulation, since there is always a potential for unexpected and undesired interactions.
More recently, attention has begun to shift from the clay and sand based compositions for household animal litters to various agricultural waste products. While cat litter is not as a rule composted, due to health concerns, the ability to flush the waste litter into a household septic system is desirable. Agricultural products tend to be more bio-compatible with the septic system. Furthermore, sand and clay-based products are also much more dense than the agricultural counterparts, and so are more inconvenient to transport by either the merchants or the homeowner. As more studies are conducted, various agricultural products are also thought to be safer and better for the animals as well. For example, it is felt that the clay compositions, when either eaten or inhaled by the animal, produce negative consequence. This is of particular concern as more complex ingredients are compounded with the clay to enhance desired characteristics. In contrast, most agricultural products may be eaten with little if any health concern.
As a result of the benefits of using agricultural products as sorbents, much research and development has been conducted with regard thereto. To illustrate this point adequately, the following United States patents are referenced, the relevant teachings of which are incorporated herein by reference. In U.S. Pat. No. 3,983,842 by Marion et al, entitled “Peanut hull animal litter”, the inventors describe grinding and pelletizing peanut hulls for making animal litter, adding other ingredients to improve clumping and help odor absorption. U.S. Pat. No. 4,206,718 by Brewer, entitled “Animal litter process,” describes a process of manufacture and materials therefor including various gelatinizable plant flours. U.S. Pat. No. 4,217,858 by Dantoni, entitled “Method of making animal litter,” describes grinding, separating inner and outer hull parts, and treating then pelletizing peanut hulls for litter making. U.S. Pat. No. 4,258,660 by Pris et al, entitled “Animal litter composition,” describes a litter composition including straw, grain, grass, sunflower hulls, alfalfa, and binder. U.S. Pat. No. 5,041,410 by Ivie, entitled “Method of processing peanut hulls,” describes the crushing and pelletizing of peanut hulls to make pesticide and fertilizer carriers, and moisture absorbent material. U.S. Pat. No. 5,067,984 by Starr, entitled “Oil absorbent,” describes a flour and mustard paste product for absorbing oil. U.S. Pat. No. 5,109,804 by Chikazawa, entitled “Coated animal litter,” describes popping cereal grains, tapioca, sweet potato, and white potato, and treating the puffed material with various chemicals to produce a litter material. U.S. Pat. No. 5,152,250 by Loeb, entitled “Agglomerating biodegradable animal litter and method of manufacture,” describes a mixture of ground peanut hulls and grain flour with an oil adherent to prevent dusting for use as a clumping litter material. U.S. Pat. No. 5,209,185 by Chikazawa, entitled “Artificial litter for pets comprising tapioca,” describes using food grade tapioca or tapioca/corn expanded pellets coated with zeolite and with other agents for scent, color, and chemical preservation. U.S. Pat. No. 5,215,041 by Krahenbuhl, entitled “Method for the manufacture of animal litter and animal litter,” describes the use of industrial fiber and household waste processed to make animal litter. U.S. Pat. No. 5,216,980 by Kiebke, entitled “Hydrating cat litter and litter additive,” describes a grain granule kitty litter, and may include clay, scent, and oil additive. U.S. Pat. No. 5,219,818 by Ivie, entitled “Method of processing peanut hulls and peanut hull granule product,” describes grinding and pelletizing peanut hulls for use “as carriers of chemical agents and as moisture absorbent materials for use in various industrial processes.” U.S. Pat. No. 5,229,348 by Ivie, entitled “Animal litter granules and method of processing peanut hulls in producing cat litter,” describes crushing peanut hulls, then compressing them into granules and adding other ingredients for good smell and to prevent mold, for use as cat litter. U.S. Pat. No. 5,266,547 by Wollrich, entitled “Diatomaceous earth containing adsorbent, method for making, and methods of use thereof,” describes a mix of vinegar, diatomaceous earth, and sugar for oil absorption. U.S. Pat. No. 5,448,967 by Ryan, entitled “Product for deodorizing and sanitizing horse stalls, and to a process of making the product,” describes a mixture of cereal grains, and kelp that is fermented to produce enzymes helpful in reducing odor, then added to diatomaceous earth to make a sanitizing powder. U.S. Pat. No. 5,605,114 by Peltenburg et al, entitled “Absorbent material comprising dried vegetable pulp and its use for treating organic waste,” describes the use of dried extraction pulp, such as beet, chicory root, or Jerusalem artichoke tuber, to make cat litter and other absorbing materials. U.S. Pat. No. 5,690,052 by Sladek, entitled “Method for sorbing liquid using ground wheat grain litter,” describes a ground cereal grain litter that absorbs and clumps. U.S. Pat. No. 5,975,018 by Otoguro, entitled “Discharged urine or other waste fluids processing material for pet animals,” describes a pellet made of “a wide variety of pulps (virgin pulp, old paper pulp, pulp residue passed through a paper-making mesh in the paper-making process, or paper-making sludge whose content of inorganic filler such as calcium carbonate is appropriately adjusted), paper powder, sawdust, wood powder, bean-curd refuse, rice hulls, coffee bean hulls, coffee been residue, tea hulls, activated carbon, and the like”. U.S. Pat. No. 6,014,947 by Sladek et al, entitled “Ground grain animal litter,” describes a ground grain litter material described as being suitable for sorbing any aqueous liquid. Milo is introduced to reduce dusting. U.S. Pat. No. 6,098,569 by Kent et al, entitled “Animal litter, process for preparing animal litter, and method for removal of animal waste,” describes the use of grain germ (corn germ was discussed and used in examples) and other ingredients to make animal litter. U.S. Pat. No. 6,216,634 by Kent et al, entitled “Animal litter, process for preparing animal litter, and method for removal of animal waste,” describes grain-germ based (preferable corn) clumping animal litter. U.S. Pat. No. 6,220,206 by Sotillo et al, entitled “Method for producing a cat litter from grain milling byproducts,” describes the use of grain milling waste products to manufacture litter pellets. U.S. Pat. No. 6,568,349 by Hughes et al, entitled “Ground grain animal litter,” patent describes pelletized or crumbled ground grain and wood mix litter. U.S. Pat. No. 6,817,315 by Tsengas et al, entitled “Cat litter,” describes use of spent distiller's grain for making litter. U.S. published applications 2003/0020043 and 2004/0086541, each by Barresi et al and entitled “Biodegradable sorbents,” discuss spent grain sorbents. As can be appreciated from the foregoing, prior artisans have contemplated such diverse agricultural by-products as spent distiller's grain, peanut hulls, saw dust, and beet pulp.
In addition to the foregoing, some prior artisans have also contemplated the use of various bean and grain products. The following U.S. patents are incorporated herein by reference as being exemplary of such attempts and knowledge. U.S. Pat. No. 5,230,305 by House, entitled “Scoopable cat litter and method,” describes a litter material made of “farinaceous material” including seeds, tubers, and roots, with cereal grain specifically focused on. U.S. Pat. No. 5,361,719 by Kiebke, entitled “Biodegradable hydrating cat litter,” describes a litter composition including use of pulse crops as one component. It further addresses adding cat-attractant scent. U.S. Pat. No. 5,526,770 by Kiebke, entitled “Biodegradable dustless cat litter,” describes the use of pulse crops and beans for use as a base in making cat litter. It is not specific in the type of beans being addressed. U.S. published application 2003/0004479 by Ueda, entitled “Water-absorbing agent composition and method for production thereof, absorptive article and absorbing material,” describes compositions for super-absorbent materials as might be used in diapers or sanitary napkins, and includes among the possible ingredients “adzuki, licorice, broad beans, and soybeans”. U.S. Pat. No. 4,727,824 by Ducharme et al, entitled “Absorbent composition, method of making and using same,” describes a composition for pet litter or for absorbing aqueous or oleophilic materials. The text repeatedly addresses use of soybeans and in the summary of the invention describes “protein from bean or seed sources such as soybean or flaxseed and the like also provide suitable binders”. U.S. Pat. No. 4,883,021, also by Ducharme et al, entitled “Absorbent composition,” describes a composition for pet litter or for absorbing aqueous or oleophilic materials. Soybeans and protein from bean or seed sources such as soybean or flaxseed and the like are described. U.S. Pat. No. 5,207,830 by Cowan et al, entitled “Lightweight particulate cementitious materials and process for producing same,” describes a foamed cementitious material that may contain guar or locust bean gum among other similar materials to provide cohesiveness and clumping when wetted by urine or similar liquids. U.S. Pat. No. 5,801,116 by Cottrell et al, entitled “Process for producing polysaccharides and their use as absorbent materials,” describes the use of locust or guar bean gum as a component of a manufactured absorbent material. U.S. Pat. No. 6,287,550 by Trinh et al, entitled “Animal care system and litter with reduced malodor impression,” describes the composition of an organic litter including “Protein such as gluten found in wheat flour, or protein from bean or seed sources such as soybean or flaxseed and the like also provide suitable binders.” Only soybeans are mentioned by name. U.S. Pat. Nos. 6,405,677, 6,622,658, and 6,868,802 each by McPherson et al and entitled “Animal litter, process for preparing animal litter and method of removal of animal waste,” describe an animal litter using seed material including soybeans and soy bean meal, and addresses addition of cohesiveness agents to improve clumping. U.S. published application 2003/0205204 by Wang et al, entitled “Animal litter, process for preparing animal litter, and method for removal of animal waste,” describes the use of “meals or flours from grain, beans, grass, and the like, which are typically thought of as agriculturally derived meals or flours” in compacted cohesive animal litter. Soybeans are the only specifically mentioned member of the beans described therein. U.S. published application 2004/0157734 by Mertens et al, entitled “Supersuperabsorbent polymers, preparation thereof and use thereof,” describes the use of carob, guar, or locust bean flour as a component of a hydrogel absorber. Finally, U.S. Pat. No. 5,021,390 by Hatton, entitled “Liquid hydrocarbon absorbent composition and method,” describes an absorbent system that does not absorb water, but readily absorbs oils and greases even from water surfaces, using guar bean, linseed, locust bean and other related leguminous plant seeds.
Clearly, a very substantial amount of research and development effort has been invested in the development of better sorbents using economically effective agricultural by-products. Nevertheless, these materials have heretofore been first a by-product, with less-than-desirable performance.
Performance enhancing additives are commonly compounded therewith, to better serve the needs of the sorbent marketplace. Heretofore, there was not a good ability to optimize the performance directly, while using the economically effective agricultural by-products. What is desired then is a base composition or ingredient which offers as many of the desired features as possible with as few of the undesired features, and which thereby reduces or eliminates the need for additional additives and the consideration of complex or unanticipated interactions. Most preferably, a modern sorbent will additionally permit handling with as little special precaution or consideration as possible.